Formula: W
Native element
Crystal System: Isometric
Specific gravity: 19.226 calculated
Hardness: 7.5 mohs
Streak: Grey
Colour: Silver-white to steel-grey
Melting point: 3,422oC, the highest melting point of all metals (ChC).
Boiling point: 5,550oC
Abundance in the Earth’s crust: 1.25 parts per million by mass, 0.1 parts per million by moles
Abundance in the Solar System: 4 parts per billion by mass, 30 part per trillion by moles
Environments
Placer deposits
Hydrothermal environments
Tungsten has been extracted from its ore for many years, and thought not to exist in the native state, but in 2011
it was approved as a mineral species, after being found at the type locality as a native element. When present in compounds,
tungsten exists mostly in the oxidation state VI, as W6+
(ChC).
Localities
At the type locality, the Bolshaya Polya River, Khanty-Mansi Autonomous Okrug, Russia, native tungsten has been found
in gold placers, occurring as polycrystalline grains and masses, and rarely as
cubo-octahedra, associated with yttrialite-(Y),
quartz, phengite and
siderite
(MM 85.1.76-81, HOM).
At the Rai-Iz Ophiolite Massif, Tyumen Oblast, Russia, native tungsten has been found in heavy concentrates from
crushed quartz (HOM), and in quartz
veins in the Mt Neroyka rock-crystal field, Ust–Puiva, Tyumenskaya Oblast, Russia
(MM 85.1.76-81, HOM).
Tungsten-bearing minerals include:
Sulphides
catamarcaite
Oxides
hydrokenoelsmoreite
tewite
wumuite
Oxychlorides
pinalite
Tungstates
cuprotungstite
ferberite
hübnerite
hydroplumboelsmoreite
raspite
ronpetersonite
russellite
scheelite
stolzite
yttrotungstite-(Y)
Nesosilicates
welinite
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